WO2017026445A1 - Composite film and method for producing same - Google Patents

Composite film and method for producing same Download PDF

Info

Publication number
WO2017026445A1
WO2017026445A1 PCT/JP2016/073299 JP2016073299W WO2017026445A1 WO 2017026445 A1 WO2017026445 A1 WO 2017026445A1 JP 2016073299 W JP2016073299 W JP 2016073299W WO 2017026445 A1 WO2017026445 A1 WO 2017026445A1
Authority
WO
WIPO (PCT)
Prior art keywords
epoxy resin
fiber sheet
composite membrane
composite film
producing
Prior art date
Application number
PCT/JP2016/073299
Other languages
French (fr)
Japanese (ja)
Inventor
秀樹 加賀田
俊和 小田
紀生 石塚
敬亘 辻井
圭太 榊原
佐藤　貴哉
Original Assignee
株式会社エマオス京都
国立大学法人京都大学
独立行政法人国立高等専門学校機構
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社エマオス京都, 国立大学法人京都大学, 独立行政法人国立高等専門学校機構 filed Critical 株式会社エマオス京都
Publication of WO2017026445A1 publication Critical patent/WO2017026445A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/26—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a composite membrane that can be used as, for example, a separator for a secondary battery, a filtering agent, and the like, and a method for manufacturing the same.
  • Porous monoliths having a co-continuous structure have been investigated for many applications.
  • use as a separating agent in a chromatography column see, for example, Patent Document 1
  • use as a prosthetic limb structure by combining a monolith and a reinforcing material for example, see Patent Document 2, etc.
  • lithium ion Use as a battery separator see, for example, Patent Documents 3 and 4
  • application of a metal catalyst to a monolith as a column reactor see, for example, Patent Document 5
  • an object of the present invention is to provide a composite membrane that is a thin film and has sufficient mechanical strength and sufficient porosity, and is suitable for use as a separator for a secondary battery, a filtering agent, or the like.
  • the present invention has the following configuration. That is, the composite film according to the present invention comprises a cured epoxy resin porous body having a three-dimensional network skeleton structure and communicating voids, and a cellulose fiber sheet.
  • the method for producing a composite film according to the present invention includes impregnating a cellulose fiber sheet with an epoxy resin composition containing an epoxy resin, a curing agent, and a porogen, and curing the epoxy resin by heating the obtained impregnated material. Then, the porogen is removed from the obtained cured product.
  • the composite membrane according to the present invention is a thin film having sufficient mechanical strength, and has excellent characteristics such as sufficient ion permeability, air permeability and liquid permeability.
  • the composite membrane according to the present invention is not only excellent in the balance between the thin film and the mechanical strength, but also has sufficient ion permeability, air permeability, and liquid permeability, so that it can be used as a separator for a secondary battery or a filtering agent. Is suitable for use.
  • the composite film which concerns on the said this invention provided with the outstanding characteristic at low cost can be manufactured.
  • FIG. 2 is a scanning electron microscope (SEM) photograph of a cross section of a monolith structure in a composite film according to Example 1; 2 is a scanning electron microscope (SEM) photograph of the film surface of the composite film according to Example 1.
  • FIG. 6 is a scanning electron microscope (SEM) photograph of the film surface of the composite film according to Example 4.
  • the composite membrane of the present invention comprises a cured epoxy resin porous material having a three-dimensional network skeleton structure and communicating voids, and a cellulose fiber sheet.
  • the composite membrane of the present invention preferably has a porosity of 20% to 70%. If the porosity is 20% or more, sufficient ion permeability and air permeability or liquid permeability can be obtained. If the porosity is 70% or less, sufficient mechanical strength as a composite film can be obtained. However, the required mechanical strength can vary depending on the application, and the porosity may be 70% or more as long as it has a mechanical strength suitable for the application.
  • the composite membrane of the present invention preferably has an average pore size of 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more. If the average pore size is too small, sufficient ions tend not to pass through when used as a secondary battery separator or the like.
  • the composite membrane of the present invention preferably has an average pore size of 10 ⁇ m or less, more preferably 5 ⁇ m or less, and further preferably 3 ⁇ m or less as a separator. If the average pore diameter is too large, when the thickness of the composite membrane is thin (for example, 20 ⁇ m or less), there is a possibility that one hole penetrates the composite membrane. In this case, the dendrite resistance and filterability are low. There is a risk that the mechanical strength as a thin film cannot be obtained. For other uses, such as filtration, depending on the size of the object, about 0.1 to 100 ⁇ m can be used.
  • the method for producing a composite film of the present invention was obtained by impregnating a cellulosic fiber sheet with an epoxy resin composition containing an epoxy resin, a curing agent and a porogen, and curing the epoxy resin by heating the resulting impregnated material. Remove the porogen from the cured product.
  • epoxy resin used with the manufacturing method of the composite film of this invention aromatic epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, etc. are mentioned. More specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, fluorene-containing epoxy resin, triglycidyl isocyanurate, alicyclic glycidyl ether type epoxy resin, alicyclic glycidyl ester type epoxy Examples thereof include resins and novolac type epoxy resins. Two or more types can be used in combination. Among these, an epoxy resin having an epoxy equivalent of 600 or less and being soluble in porogen is particularly preferable.
  • the above-mentioned curing agent used in the method for producing a composite film of the present invention is not particularly limited, and examples thereof include amines, polyamidoamines, acid anhydrides, and phenols. More specifically, aliphatic polyamidoamines composed of metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, bis (4-amino-3-methylcyclohexyl) methane, bis (4-aminocyclohexyl) methane, polyamines and dimer acid. Etc.
  • a curing accelerator can be used.
  • the curing accelerator is not particularly limited, and any known compound can be used.
  • tertiary amines such as triethylamine and tributylamine, 2-phenol-4-methylimidazole, 2-ethyl-4-methyl Imidazoles such as imidazole and 2-phenol-4,5-dihydroxymethylimidazole can be preferably used.
  • the term “porogen” refers to an inert solvent or inert solvent mixture as a pore-forming agent.
  • the porogen is present in a polymerization reaction that forms a porous polymer at a certain stage of polymerization, and is removed from the reaction mixture at a predetermined stage, whereby an epoxy resin having a three-dimensional network skeleton structure and communicating voids. A cured product porous body is obtained.
  • the hydroxyl value is less than 100 (mgKOH / g)
  • the viscosity increases and it becomes difficult to increase the pore size of the formed cured epoxy resin porous material, or imparting hydrophilicity to the cured epoxy resin porous material.
  • the effect may be reduced.
  • Examples of the cellulosic fiber sheet used in the method for producing a composite membrane of the present invention include paper and non-woven fabric.
  • the cellulosic fiber in the cellulosic fiber sheet may be either natural or synthetic.
  • Cellulosic fiber sheets have better adhesion to epoxy resins than other fiber sheets.
  • the cellulosic fiber preferably has a functional group on the surface from the viewpoint of the interfacial adhesive strength between the fiber and the resin.
  • Examples of the functional group include an amino group, a glycidyl group, and a hydroxyl group.
  • the method for introducing a functional group onto the surface of the fiber is not particularly limited. For example, a surface treatment such as plasma treatment or electrolytic oxidation treatment is effective.
  • the composite membrane of the present invention is desired to be as thin as possible for the purpose of use and to have high porosity, it is desirable that the cellulosic fiber sheet to be used is thin and has a large porosity.
  • the thickness is preferably 500 ⁇ m or less, more preferably 100 ⁇ m or less, and even more preferably 30 ⁇ m or less.
  • the lower limit of the thinner one is preferably about 10 times the minimum pore diameter, and is preferably 5 ⁇ m or more from the viewpoint of strength, more preferably 10 ⁇ m or more.
  • the porosity of a cellulose fiber sheet is as large as possible.
  • the porosity is preferably 50% or more, more preferably 60% or more, and particularly preferably 70% or more.
  • a cellulose fiber sheet for example, “ultra-thin paper” (basis weight 6 g / m 2 , thickness 16 ⁇ m, use of hemp and wood fibers, specific gravity of cellulose fibers, manufactured by Nippon Paper Papillia Co., Ltd.
  • the porosity is 74%).
  • the manufacturing method of the composite film of the present invention using the above components will be described in detail.
  • the cured epoxy resin porous material described in the specification of Japanese Patent Application No. 2005-2550 and the international application PCT / JP2006 / 300069 based thereon is a prior patent application by the present inventors.
  • the manufacturing method can be referred to.
  • the epoxy resin, the curing agent, and the porogen are included.
  • a composite membrane can be produced by heating and reacting an impregnation product obtained by impregnating a cellulose fiber sheet with an epoxy resin composition.
  • the epoxy resin and the curing agent are selected so that, for example, the ratio of the curing agent equivalent to 1 equivalent of the epoxy group is in the range of 0.6 to 1.5, the epoxy resin and the curing agent, and non-reactive with them.
  • an epoxy resin composition comprising a porogen that is soluble in
  • the ratio of the curing agent equivalent to 1 equivalent of epoxy group is smaller than 0.6, the crosslinking density of the cured product is lowered, and the heat resistance and solvent resistance may be lowered.
  • the ratio is larger than 1.5, the number of unreacted functional groups in the curing agent increases, and the unreacted functional groups remain in the cured product, or the increase in the crosslinking density is hindered. There is a fear.
  • the cellulose resin sheet is impregnated with the epoxy resin composition. After impregnation, it is preferable to sufficiently defoam bubbles remaining in the fiber bundle.
  • a predetermined polymerization is performed. Polymerization is carried out by heating to temperature.
  • the method (3) using the thickened epoxy resin composition has an advantage that a skin layer (a skin layer having no or very few pores on the surface in contact with air) does not occur.
  • the thickened epoxy resin composition is used as in (3), and the uncured epoxy resin composition flows without using a support substrate on a flat plate as in (1) and (2). This is to prevent the film from sagging due to the property and to make the film thickness non-uniform, but at the same time, it has the effect of preventing the formation of the skin layer.
  • thickener Various commercially available thickeners can be used as the thickener, and among these, finely divided silica is preferred. Examples of fine silica include those sold as “Aerosil” series (produced by Nippon Aerosil Co., Ltd.), and those having a hydrophilic surface are preferred. Further, the thickener can be used not only in (3) but also in (1), (2), and (4).
  • Microphase separation can be caused by spinodal decomposition of the polymer and porogen due to polymerization induction.
  • microphase separation grows, the co-continuous structure due to the polymer and porogen becomes unstable and attempts to transfer to a particle aggregate structure.
  • the polymer is cross-linked three-dimensionally to form the co-continuous structure. Can be fixed (freeze-fixed).
  • the process of heating the impregnated product to obtain a cured product usually includes polymerization, crosslinking, phase separation, and curing steps, and these steps may proceed in combination in some cases.
  • phase separation occurs due to spinodal decomposition and a co-continuous structure develops, but as described above, the phase separation further proceeds and the epoxy resin crosslinks before the co-continuous structure disappears.
  • the structure is fixed by advancing the reaction to produce a desired three-dimensional network skeleton structure, or a three-dimensional network skeleton structure in which three-dimensional network skeleton and spherical fine particles are mixed, and a porous body having communicating voids. It becomes possible to do.
  • the structure of the obtained porous body can be confirmed by, for example, observation with a scanning electron microscope.
  • the above-mentioned porosity, average pore diameter, and pore diameter distribution in the composite membrane of the present invention vary depending on the type and usage ratio of the epoxy resin, curing agent and porogen used, or polymerization temperature conditions. Therefore, by creating a phase diagram of the system and selecting optimum conditions, the porosity, average pore diameter, and pore diameter distribution in the above range can be obtained.
  • the composite membrane of the present invention is a thin film and has sufficient mechanical strength, and has sufficient ion permeability, air permeability, and water permeability. Therefore, the composite membrane is used as a separator for a secondary battery such as a lithium ion battery or a filtering agent. be able to. Moreover, the composite film obtained from the fact that the strength is improved by compounding with the cellulosic fiber sheet can be used after being processed into a shape other than planar use such as a cylindrical shape or a box shape.
  • Porosity (%) (1 ⁇ W / ⁇ V) ⁇ 100 here, W: Dry weight of composite membrane (g) V: Apparent volume of the composite membrane (cm 3 ) ⁇ : solid content density of composite membrane (g / m 3 ) It is.
  • the solid content density of the composite membrane is a value measured according to JIS-K-7112 (Method B) after defoaming the composite membrane in ethanol.
  • ⁇ Average pore size> Estimated from electron micrographs. It can be understood that the average pore size of the composite membrane is usually within the numerical range of the average pore size of the composite membrane.
  • Cellulose-based fiber sheet 1 is “ultra-thin paper” manufactured by Nippon Paper Papillia Co., Ltd., and cellulose-based fiber sheets 2 and 3 and PET paper are also manufactured by (the prototype).
  • Example 1 ⁇ Preparation of epoxy resin composition>
  • an epoxy resin 1 part by weight of an epoxy compound represented by the following formula (1) having an epoxy equivalent of 95 to 110 (average 102) (trade name “Tetrad-C”, Mitsubishi Gas Chemical Industries, Ltd.), as a curing agent, 0.575 parts by weight of bis (4-aminocyclohexyl) methane (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (2) having an amine value of 520 to 550, the following formula having an average molecular weight of 200 as a porogen Using 4 parts by weight of polyethylene glycol 200 represented by (3) (manufactured by Wako Pure Chemical Industries, Ltd.) and mixing them with “Awatori Netaro” of a rotation / revolution mixer, an epoxy resin composition is obtained. Obtained. The viscosity was 135 mPa ⁇ S at 25 ° C. (The viscometer used was a vibration viscometer “VM-10-AM, manufactured by Seconic Corporation
  • ⁇ Production of composite membrane> A 2 wt% aqueous solution of polyvinyl alcohol (PVA) (manufactured by Wako Pure Chemical Industries, Ltd.) having an average polymerization degree n of 3500 and a saponification degree of 86 to 90% was applied to two 75 mm ⁇ 75 mm glass plates with a spin coater. Then, after coating at 2,000 rpm for 20 seconds, annealing was performed at 105 ° C. for 1 hour to obtain two glass plates on which a polyvinyl alcohol layer was formed.
  • PVA polyvinyl alcohol
  • the cellulose fiber sheet 1 shown in Table 1 cut to the same size as the glass plate (“Ultra-thin paper” from Nippon Paper Papillia Co., Ltd.) The amount was 6 g / m 2 , the thickness was 16 ⁇ m, hemp and wood fiber used, and the specific gravity of cellulose fiber was calculated as 1.5, and the porosity was 74%)).
  • the epoxy resin composition prepared above is placed in the center of the fiber sheet, and another glass plate on which the polyvinyl alcohol layer is formed is placed on the epoxy resin composition so that the polyvinyl alcohol layer-forming surface is in contact with the epoxy resin composition layer.
  • the glass plate sandwiched with the impregnated material obtained by impregnating the fiber sheet with the epoxy resin composition as described above is heated at 110 ° C. for 1 hour to cure the epoxy compound in the epoxy resin composition layer.
  • a cured product was obtained.
  • the cured product was poured into warm water adjusted to a temperature of 80 to 90 ° C. and left for 60 minutes to dissolve a part of the polyvinyl alcohol layer, thereby peeling off the glass plate.
  • the cured product is poured into warm water composed of pure water adjusted to a temperature of 50 to 60 ° C., and left for 2 hours with proper stirring of the warm water, whereby polyethylene glycol contained in the epoxy resin composition layer after heating is contained.
  • the process of extracting 200 was repeated three times and then dried overnight at 60 ° C. under vacuum to obtain a composite film without a skin layer composed of a fiber sheet and a porous epoxy resin cured product.
  • the thickness of the obtained composite membrane was 24 ⁇ m, the fiber content was 35% by weight, the porosity of the composite membrane was 43%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.8 to 1. It was 2 ⁇ m.
  • the composite film tensile strength was 75.4 MPa in the MD direction (fiber direction of the fiber sheet) and 17.3 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet).
  • the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 ⁇ 4 S / cm or more, and it was confirmed that the ionic conductivity was high.
  • a scanning electron microscope (SEM) photograph is shown in FIG.1 and FIG.2.
  • FIG. 1 is an SEM photograph of a cross section of the monolith structure taken by cutting the composite film
  • FIG. 2 is an SEM photograph of the film surface of the composite film.
  • Example 2 In Example 1, it replaced with the cellulose fiber sheet 1 of the said Table 1, and it replaced with the cellulose fiber sheet 2 of the said Table 1, and was the same as Example 1, and the composite film which concerns on Example 2 Got.
  • the thickness of the obtained composite membrane was 38.2 ⁇ m
  • the porosity of the composite membrane was 49%
  • the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.8 to 1.2 ⁇ m.
  • the composite film tensile strength was 40.6 MPa in the MD direction (fiber direction of the fiber sheet) and 23.1 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet).
  • the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 ⁇ 4 S / cm or more, and it was confirmed that the ionic conductivity was high.
  • Example 4 As the thickener for the epoxy resin composition of Example 1, Aerosil 130 (manufactured by Nippon Aerosil Co., Ltd.) was used in a proportion of 5% by weight with respect to polyethylene glycol 200. ”To obtain a thickened epoxy resin composition.
  • the viscosity was 840 mPa ⁇ s at 25 ° C. (The viscometer used was a vibration viscometer “VM-10-AM, manufactured by Seconic Corporation”).
  • the cellulosic fiber sheet 1 shown in Table 1 cut into a size of 15 cm ⁇ 30 cm (“ultra-thin paper” from Nippon Paper Papillia Co., Ltd.) (basis weight 6 g / m 2 The thickness is 16 ⁇ m, hemp and wood fibers are used, and the specific gravity of cellulose fiber is calculated as 1.5. The porosity is 74%)), and the thickened epoxy resin composition is placed in the center of the fiber sheet. After extending and impregnating so as to spread over the entire fiber sheet, an impregnation product having a uniform film thickness was obtained by pulling it up through two lightly pressed bar coaters (No. 3).
  • the thickness of the obtained composite membrane was 23 ⁇ m, the fiber content was 35% by weight, the porosity of the composite membrane was 43%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.2 to 0.00. It was 5 ⁇ m.
  • the composite film tensile strength was 70.5 MPa in the MD direction (fiber direction of the fiber sheet) and 16.3 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet).
  • the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 ⁇ 4 S / cm or more, and it was confirmed that the ionic conductivity was high.
  • a scanning electron microscope (SEM) photograph of the obtained composite film is shown in FIG.
  • FIG. 3 is an SEM photograph of the film surface in the composite film, and it can be seen that it has a surface without a skin layer (has holes on the surface).
  • Example 1 In the same manner as in Example 1, instead of the cellulosic fiber sheet 1, a 25 ⁇ m-thick Teflon (registered trademark) film was cut to a width of 3 mm and placed on the periphery of the four sides of the glass plate to form a spacer. A film was formed only with the composition.
  • the resulting epoxy porous body had a thickness of 23 ⁇ m and a tensile strength of 10.4 MPa (the fiber sheet was not inserted so that there was no directionality in the strength), and the average pore diameter of the epoxy porous body confirmed with a scanning electron microscope Was 0.8 to 1.2 ⁇ m. Further, when the ionic conductivity of the obtained porous membrane was measured by complex impedance measurement, it was 10 ⁇ 4 S / cm or more, and it was confirmed that the ionic conductivity was high.
  • Example 2 In Example 1, it replaced with the cellulose fiber sheet 1 of the said Table 1, and obtained the composite film which concerns on the comparative example 2 like Example 1 except having used the PET paper of the said Table 1. .
  • the thickness of the obtained composite membrane was 13 ⁇ m
  • the porosity of the composite membrane was 23%
  • the tensile strength was 24.8 MPa in the MD direction (fiber direction of the fiber sheet)
  • the CD direction with the fibers of the fiber sheet) (Perpendicular direction) was 9.8 MPa, which was almost the same as that of the PET paper before composite.
  • the average pore size of the composite membrane confirmed with a scanning electron microscope was 0.8 to 1.2 ⁇ m.
  • Example 4 From the results shown in Examples 1 to 4, the composite film of the cellulose fiber sheet and the cured epoxy resin porous material is a thin film, and the respective materials without greatly reducing the porosity. It was found that a material having a strength equal to or greater than the addition of the above strengths can be obtained. On the other hand, it was found from the comparison between each example and Comparative Example 2 that it is important to use a cellulosic fiber sheet rather than simply using a fiber sheet. Comparing Example 1 and Example 4, it can be seen that Example 4 has a smaller hole diameter. In Example 4, unlike Example 1, since there is no glass plate at the time of curing, it is presumed that the hole diameter was reduced because it was directly heated and the substantial curing temperature was high.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Cell Separators (AREA)
  • Reinforced Plastic Materials (AREA)

Abstract

The present invention provides a composite film suitable for use as a filter agent or a separator for secondary batteries that is lightweight and has sufficient mechanical strength in addition to good ion conductivity. This composite film includes an epoxy resin porous cured body having a three-dimensional network skeleton structure and communicating voids, and a cellulose fiber sheet. This method for producing a composite film comprises: impregnating a cellulose fiber sheet with an epoxy resin composition including an epoxy resin, a curing agent, and a porogen; heating the resulting impregnated material and curing the epoxy resin; and removing the porogen from the resulting cured product.

Description

複合膜及びその製造方法Composite membrane and manufacturing method thereof
　本発明は、例えば、二次電池用セパレータや濾過剤などとして利用することのできる複合膜及びその製造方法に関する。 The present invention relates to a composite membrane that can be used as, for example, a separator for a secondary battery, a filtering agent, and the like, and a method for manufacturing the same.
　共連続構造を有する多孔質のモノリスは多くの用途に検討されている。例えば、クロマトグラフィーのカラムに分離剤として利用すること（例えば、特許文献１等参照）、モノリスと強化材を組み合わせて義肢の構造体として利用すること（例えば、特許文献２等参照）、リチウムイオン電池のセパレータとして利用すること（例えば、特許文献３，４等参照）、モノリスに金属触媒を付与してカラムリアクターとして利用すること（例えば、特許文献５等参照）などが検討されている。
　これらの用途の中で、数十ミクロン程度の薄い膜として利用するセパレータや濾過剤の用途を考えた場合、エポキシモノリスだけからなる膜では十分に強度があるとはいえない。 Porous monoliths having a co-continuous structure have been investigated for many applications. For example, use as a separating agent in a chromatography column (see, for example, Patent Document 1), use as a prosthetic limb structure by combining a monolith and a reinforcing material (for example, see Patent Document 2, etc.), lithium ion Use as a battery separator (see, for example, Patent Documents 3 and 4), application of a metal catalyst to a monolith as a column reactor (see, for example, Patent Document 5), and the like have been studied.
Among these uses, when considering the use of a separator or a filtering agent used as a thin film of about several tens of microns, it cannot be said that a film made of only an epoxy monolith has sufficient strength.
　この強度を改善するためにエポキシ樹脂の種類の検討（例えば、特許文献６等参照）や、炭素繊維とガラス繊維を補強材に利用する方法（例えば、特許文献７等参照）、補強材にセルロースナノファイバーを添加する方法（例えば、非特許文献１等参照）も提案されている。 In order to improve this strength, the type of epoxy resin (for example, see Patent Document 6), a method of using carbon fiber and glass fiber as a reinforcing material (for example, see Patent Document 7), cellulose for the reinforcing material, etc. A method of adding nanofibers (see, for example, Non-Patent Document 1) has also been proposed.
国際公開第２００６／１２６３８７号International Publication No. 2006/126387 特開２００８－０１３６７２号公報JP 2008-013672 A 特許第４９４０３６７号公報Japanese Patent No. 4940367 特開２０１３－０２０９６０号公報JP 2013-020960 A 特開２０１０－２０７７７７号公報JP 2010-207777 A 特開２０１３－０２０９４７号公報JP 2013-020947 A 国際公開第２０１１／０９８７９４号International Publication No. 2011/098794
　しかし、特許文献６，７や非特許文献１で提案されているような技術では、まだ性能やコスト、製造方法において難がある。
　そこで、本発明の課題は、薄膜で十分な機械強度を有すると共に、十分な空隙率を有し、二次電池用セパレータや濾過剤などとしての使用に好適な複合膜を提供することにある。 However, the techniques proposed in Patent Documents 6 and 7 and Non-Patent Document 1 still have difficulty in performance, cost, and manufacturing method.
Accordingly, an object of the present invention is to provide a composite membrane that is a thin film and has sufficient mechanical strength and sufficient porosity, and is suitable for use as a separator for a secondary battery, a filtering agent, or the like.
　本発明は、上記課題を解決するため、下記の構成を備える。
　すなわち、本発明にかかる複合膜は、三次元網目状骨格構造及び連通する空隙を有するエポキシ樹脂硬化物多孔体とセルロース系繊維シートとを含んでなる。 In order to solve the above problems, the present invention has the following configuration.
That is, the composite film according to the present invention comprises a cured epoxy resin porous body having a three-dimensional network skeleton structure and communicating voids, and a cellulose fiber sheet.
　また、本発明にかかる複合膜の製造方法は、エポキシ樹脂、硬化剤及びポロゲンを含むエポキシ樹脂組成物をセルロース系繊維シートに含浸し、得られた含浸物を加熱して前記エポキシ樹脂を硬化し、得られた硬化物から前記ポロゲンを除去する。 In addition, the method for producing a composite film according to the present invention includes impregnating a cellulose fiber sheet with an epoxy resin composition containing an epoxy resin, a curing agent, and a porogen, and curing the epoxy resin by heating the obtained impregnated material. Then, the porogen is removed from the obtained cured product.
　本発明による複合膜は、薄膜で十分な機械強度を有すると共に、十分なイオン通過性や通気性ないし通液性を有するという、優れた特性を有する。本発明による複合膜は、このように、薄膜と機械強度のバランスに優れるのみならず、十分なイオン通過性や通気性ないし通液性に優れているため、二次電池用セパレータや濾過剤としての使用に好適である。
　そして、本発明に係る複合膜の製造方法によれば、低コストで優れた特性を備える上記本発明に係る複合膜を製造することができる。 The composite membrane according to the present invention is a thin film having sufficient mechanical strength, and has excellent characteristics such as sufficient ion permeability, air permeability and liquid permeability. Thus, the composite membrane according to the present invention is not only excellent in the balance between the thin film and the mechanical strength, but also has sufficient ion permeability, air permeability, and liquid permeability, so that it can be used as a separator for a secondary battery or a filtering agent. Is suitable for use.
And according to the manufacturing method of the composite film which concerns on this invention, the composite film which concerns on the said this invention provided with the outstanding characteristic at low cost can be manufactured.
実施例１にかかる複合膜におけるモノリス構造断面の走査型電子顕微鏡（ＳＥＭ）写真である。2 is a scanning electron microscope (SEM) photograph of a cross section of a monolith structure in a composite film according to Example 1; 実施例１にかかる複合膜における膜表面の走査型電子顕微鏡（ＳＥＭ）写真である。2 is a scanning electron microscope (SEM) photograph of the film surface of the composite film according to Example 1. FIG. 実施例４にかかる複合膜における膜表面の走査型電子顕微鏡（ＳＥＭ）写真である。6 is a scanning electron microscope (SEM) photograph of the film surface of the composite film according to Example 4.
　以下、本発明にかかる複合膜とその製造方法の好ましい実施形態について詳しく説明するが、本発明の範囲はこれらの説明に拘束されることはなく、以下の例示以外についても、本発明の趣旨を損なわない範囲で適宜変更実施し得る。 Hereinafter, preferred embodiments of the composite membrane and the method for producing the same according to the present invention will be described in detail. However, the scope of the present invention is not limited to these descriptions, and the gist of the present invention is not limited to the following examples. Changes can be made as appropriate without departing from the scope.
　〔複合膜〕
　本発明の複合膜は、三次元網目状骨格構造及び連通する空隙を有するエポキシ樹脂硬化物多孔体とセルロース系繊維シートとを含んでなる。 [Composite membrane]
The composite membrane of the present invention comprises a cured epoxy resin porous material having a three-dimensional network skeleton structure and communicating voids, and a cellulose fiber sheet.
　本発明の複合膜は、その空孔率が２０％～７０％であることが好ましい。空孔率が２０％以上であれば、十分なイオン通過性と、通気性ないし通液性が得られる。また、空孔率が７０％以下であれば、複合膜としての十分な機械強度が得られる。もっとも、求められる機械強度は用途によって異なり得るものであり、その用途に適した機械強度を有するものであるならば、空孔率７０％以上であっても構わない。
　また、本発明の複合膜は、その平均孔径が０．１μｍ以上であることが好ましく、０．２μｍ以上であることがより好ましい。平均孔径が小さすぎると、二次電池用セパレータなどとして使用した場合、十分なイオンが通過しがたい傾向にある。
　さらに、本発明の複合膜は、セパレータとしてはその平均孔径は１０μｍ以下であることが好ましく、より好ましくは５μｍ以下、さらに好ましくは３μｍ以下である。平均孔径が大きすぎると、複合膜の厚みが薄い場合（例えば、２０μｍ以下）に、一つの孔が複合膜を貫通している状態となるおそれがあり、この場合、耐デンドライト性や濾過性が低下することになったり、薄膜としての十分な機械強度が得られなくなったりするおそれがある。その他の用途、例えば濾過用などとしては対象物の大きさ次第であり、０．１～１００μｍ程度は使用可能である。 The composite membrane of the present invention preferably has a porosity of 20% to 70%. If the porosity is 20% or more, sufficient ion permeability and air permeability or liquid permeability can be obtained. If the porosity is 70% or less, sufficient mechanical strength as a composite film can be obtained. However, the required mechanical strength can vary depending on the application, and the porosity may be 70% or more as long as it has a mechanical strength suitable for the application.
In addition, the composite membrane of the present invention preferably has an average pore size of 0.1 μm or more, more preferably 0.2 μm or more. If the average pore size is too small, sufficient ions tend not to pass through when used as a secondary battery separator or the like.
Furthermore, the composite membrane of the present invention preferably has an average pore size of 10 μm or less, more preferably 5 μm or less, and further preferably 3 μm or less as a separator. If the average pore diameter is too large, when the thickness of the composite membrane is thin (for example, 20 μm or less), there is a possibility that one hole penetrates the composite membrane. In this case, the dendrite resistance and filterability are low. There is a risk that the mechanical strength as a thin film cannot be obtained. For other uses, such as filtration, depending on the size of the object, about 0.1 to 100 μm can be used.
　〔複合膜の製造方法〕
　本発明の複合膜の製造方法は、エポキシ樹脂、硬化剤及びポロゲンを含むエポキシ樹脂組成物をセルロース系繊維シートに含浸し、得られた含浸物を加熱してエポキシ樹脂を硬化し、得られた硬化物からポロゲンを除去する。 [Production method of composite membrane]
The method for producing a composite film of the present invention was obtained by impregnating a cellulosic fiber sheet with an epoxy resin composition containing an epoxy resin, a curing agent and a porogen, and curing the epoxy resin by heating the resulting impregnated material. Remove the porogen from the cured product.
　まず、原料となる各成分について詳述する。
　本発明の複合膜の製造方法で用いる上記エポキシ樹脂としては、芳香族エポキシ樹脂、脂肪族エポキシ樹脂、脂環式エポキシ樹脂、複素環式エポキシ樹脂などが挙げられる。より具体的には、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ビスフェノールＡＤ型エポキシ樹脂、フルオレン含有エポキシ樹脂、トリグリシジルイソシアヌレート、脂環族グリシジルエーテル型エポキシ樹脂、脂環族グリシジルエステル型エポキシ樹脂、ノボラック型エポキシ樹脂などが挙げられる。２種以上を併用することも可能である。なかでも、エポキシ当量が６００以下でポロゲンに溶解可能なエポキシ樹脂が特に好ましい。 First, each component used as a raw material is explained in full detail.
As said epoxy resin used with the manufacturing method of the composite film of this invention, aromatic epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, etc. are mentioned. More specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, fluorene-containing epoxy resin, triglycidyl isocyanurate, alicyclic glycidyl ether type epoxy resin, alicyclic glycidyl ester type epoxy Examples thereof include resins and novolac type epoxy resins. Two or more types can be used in combination. Among these, an epoxy resin having an epoxy equivalent of 600 or less and being soluble in porogen is particularly preferable.
　本発明の複合膜の製造方法で用いる上記硬化剤としては、特に限定されないが、例えば、アミン類、ポリアミドアミン類、酸無水物、フェノール系などを挙げることができる。より具体的には、メタフェニレンジアミン、ジアミノジフェニルメタン、ジアミノジフェニルスルホン、ビス（４－アミノ－３－メチルシクロヘキシル）メタン、ビス（４－アミノシクロヘキシル）メタン、ポリアミン類とダイマー酸からなる脂肪族ポリアミドアミンなどが挙げられる。本発明においては、エポキシ樹脂と反応して水酸基を形成し、得られる多孔体に親水性を付与する機能を有する硬化剤を用いることが好ましい。 The above-mentioned curing agent used in the method for producing a composite film of the present invention is not particularly limited, and examples thereof include amines, polyamidoamines, acid anhydrides, and phenols. More specifically, aliphatic polyamidoamines composed of metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, bis (4-amino-3-methylcyclohexyl) methane, bis (4-aminocyclohexyl) methane, polyamines and dimer acid. Etc. In the present invention, it is preferable to use a curing agent having a function of reacting with an epoxy resin to form a hydroxyl group and imparting hydrophilicity to the resulting porous body.
　本発明の複合膜の製造方法においては、硬化促進剤を使用することもできる。硬化促進剤としては特に限定されず、既知のあらゆる化合物を使用することができるが、例えば、トリエチルアミン、トリブチルアミン等の三級アミン、２－フェノール－４－メチルイミダゾール、２－エチル－４－メチルイミダゾール、２－フェノール－４，５－ジヒドロキシメチルイミダゾールなどのイミダゾール類などを好適に用いることができる。 In the method for producing a composite film of the present invention, a curing accelerator can be used. The curing accelerator is not particularly limited, and any known compound can be used. For example, tertiary amines such as triethylamine and tributylamine, 2-phenol-4-methylimidazole, 2-ethyl-4-methyl Imidazoles such as imidazole and 2-phenol-4,5-dihydroxymethylimidazole can be preferably used.
　本発明において、用語「ポロゲン」とは、細孔形成剤としての不活性溶媒又は不活性溶媒混合物を指称する。ポロゲンは、重合のある段階で多孔性ポリマーを形成させる重合反応中に存在し、所定の段階でこれを反応混合物中から除去することによって、三次元網目状骨格構造及び連通する空隙を有するエポキシ樹脂硬化物多孔体が得られる。 In the present invention, the term “porogen” refers to an inert solvent or inert solvent mixture as a pore-forming agent. The porogen is present in a polymerization reaction that forms a porous polymer at a certain stage of polymerization, and is removed from the reaction mixture at a predetermined stage, whereby an epoxy resin having a three-dimensional network skeleton structure and communicating voids. A cured product porous body is obtained.
　本発明においては、ポロゲンとして、水酸基を有し、水酸基価１００（ｍｇＫＯＨ／ｇ）以上のポリアルキレングリコールまたはポリアルキレングリコール誘導体を使用することが望ましい。水酸基価が１００（ｍｇＫＯＨ／ｇ）より小さくなると粘度が高くなり、形成されるエポキシ樹脂硬化物多孔体の孔径を大きくすることが困難になったり、エポキシ樹脂硬化物多孔体への親水性の付与効果が低下することがある。エポキシ樹脂硬化物多孔体表面の水酸基量とポロゲンの水酸基当量とは密接な関係にあり、ポロゲンの水酸基価が小さくなるに連れてエポキシ樹脂硬化物表面に現れる水酸基量も減少し、表面の親水性が低下するためと考えられる。 In the present invention, it is desirable to use a polyalkylene glycol or a polyalkylene glycol derivative having a hydroxyl group and having a hydroxyl value of 100 (mgKOH / g) or more as the porogen. When the hydroxyl value is less than 100 (mgKOH / g), the viscosity increases and it becomes difficult to increase the pore size of the formed cured epoxy resin porous material, or imparting hydrophilicity to the cured epoxy resin porous material. The effect may be reduced. There is a close relationship between the amount of hydroxyl groups on the surface of the cured epoxy resin and the hydroxyl equivalent of the porogen. As the hydroxyl value of the porogen decreases, the amount of hydroxyl that appears on the surface of the cured epoxy resin also decreases. This is thought to be due to a decline.
　本発明の複合膜の製造方法に使用されるセルロース系繊維シートとしては、紙や不織布を挙げることができる。
　また、セルロース系繊維シートにおけるセルロース系繊維は、天然あるいは合成のいずれでもよい。セルロース系繊維シートは、他の繊維シートと比べて、エポキシ樹脂との密着性が良い。
　上記のセルロース系繊維は、表面に官能基を有することが、繊維と樹脂の界面接着強度の点から好ましい。官能基としては、例えば、アミノ基、グリシジル基、水酸基などが挙げられる。繊維の表面に官能基を導入する方法については、特に限定されないが、例えば、プラズマ処理や電解酸化処理などによる表面処理が有効である。
　本発明の複合膜は、その使用目的からいってできるだけ薄い膜で且つ高多孔性が望まれるので、使用するセルロース系繊維シートは薄くて空隙率の大きいものが望ましい。例えば、厚さは５００μｍ以下が好ましく、より好ましくは１００μｍ以下、さらに好ましくは３０μｍ以下である。薄い方の下限としては最小孔径の１０倍程度はあった方が良く、また強度の点からは５μｍ以上が好ましく、出来れば１０μｍ以上がより好ましい。また、本発明の複合膜の製造方法では、セルロース系繊維シートの空隙内に多孔性モノリスを形成するのでセルロース系繊維シートの空隙率はできるだけ大きいことが望ましい。具体的には、空隙率として５０％以上が好ましく、６０％以上がより好ましく、７０％以上が特に好ましい。
　このようなセルロース系繊維シートとしては、具体的には、例えば、日本製紙パピリア株式会社の「超極薄紙」（坪量６ｇ／ｍ2、厚さ１６μｍ、麻と木材繊維使用、セルロース繊維の比重を１．５として計算すると空隙率は７４％）などが好ましく挙げられる。 Examples of the cellulosic fiber sheet used in the method for producing a composite membrane of the present invention include paper and non-woven fabric.
In addition, the cellulosic fiber in the cellulosic fiber sheet may be either natural or synthetic. Cellulosic fiber sheets have better adhesion to epoxy resins than other fiber sheets.
The cellulosic fiber preferably has a functional group on the surface from the viewpoint of the interfacial adhesive strength between the fiber and the resin. Examples of the functional group include an amino group, a glycidyl group, and a hydroxyl group. The method for introducing a functional group onto the surface of the fiber is not particularly limited. For example, a surface treatment such as plasma treatment or electrolytic oxidation treatment is effective.
Since the composite membrane of the present invention is desired to be as thin as possible for the purpose of use and to have high porosity, it is desirable that the cellulosic fiber sheet to be used is thin and has a large porosity. For example, the thickness is preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 30 μm or less. The lower limit of the thinner one is preferably about 10 times the minimum pore diameter, and is preferably 5 μm or more from the viewpoint of strength, more preferably 10 μm or more. Moreover, in the manufacturing method of the composite film of this invention, since the porous monolith is formed in the space | gap of a cellulose fiber sheet, it is desirable that the porosity of a cellulose fiber sheet is as large as possible. Specifically, the porosity is preferably 50% or more, more preferably 60% or more, and particularly preferably 70% or more.
Specifically, as such a cellulose fiber sheet, for example, “ultra-thin paper” (basis weight 6 g / m 2 , thickness 16 μm, use of hemp and wood fibers, specific gravity of cellulose fibers, manufactured by Nippon Paper Papillia Co., Ltd. Preferably, the porosity is 74%).
　次に、上記各成分を用いた本発明の複合膜の製造方法について詳述する。
　本発明による複合膜の製造方法では、本発明者らによる先行特許出願である特願２００５－２５５０号及びそれに基づく国際出願ＰＣＴ／ＪＰ２００６／３０００６９の明細書に記載されたエポキシ樹脂硬化物多孔体の製造方法を参考にすることができる。具体的には、前記先行特許出願の明細書に記載の方法を採用するに際し、エポキシ樹脂と硬化剤を溶解したポロゲンを加熱して反応させる代わりに、エポキシ樹脂、硬化剤、ポロゲンを含んでなるエポキシ樹脂組成物をセルロース系繊維シートに含浸して得た含浸物を加熱反応させることで、複合膜を製造することができる。 Next, the manufacturing method of the composite film of the present invention using the above components will be described in detail.
In the method for producing a composite membrane according to the present invention, the cured epoxy resin porous material described in the specification of Japanese Patent Application No. 2005-2550 and the international application PCT / JP2006 / 300069 based thereon is a prior patent application by the present inventors. The manufacturing method can be referred to. Specifically, in adopting the method described in the specification of the prior patent application, instead of heating and reacting the porogen in which the epoxy resin and the curing agent are dissolved, the epoxy resin, the curing agent, and the porogen are included. A composite membrane can be produced by heating and reacting an impregnation product obtained by impregnating a cellulose fiber sheet with an epoxy resin composition.
　まず、エポキシ樹脂と硬化剤を、例えば、エポキシ基１当量に対する硬化剤当量の比率が０．６～１．５の範囲になるように選択し、エポキシ樹脂と硬化剤、並びにそれらと非反応性で溶解可能なポロゲンを含んでなるエポキシ樹脂組成物を調製する。
　エポキシ基１当量に対する硬化剤当量の比率が０．６より小さい場合は、硬化物の架橋密度が低くなり、耐熱性、耐溶剤性などが低下するおそれがある。また、上記比率が１．５より大きくなると、硬化剤中の未反応の官能基が多くなり、未反応のまま硬化物中に残留したり、あるいは架橋密度の増加を阻害する要因となったりするおそれがある。 First, the epoxy resin and the curing agent are selected so that, for example, the ratio of the curing agent equivalent to 1 equivalent of the epoxy group is in the range of 0.6 to 1.5, the epoxy resin and the curing agent, and non-reactive with them. To prepare an epoxy resin composition comprising a porogen that is soluble in
When the ratio of the curing agent equivalent to 1 equivalent of epoxy group is smaller than 0.6, the crosslinking density of the cured product is lowered, and the heat resistance and solvent resistance may be lowered. Moreover, when the ratio is larger than 1.5, the number of unreacted functional groups in the curing agent increases, and the unreacted functional groups remain in the cured product, or the increase in the crosslinking density is hindered. There is a fear.
　前記エポキシ樹脂組成物をセルロース系繊維シートに含浸する。含浸後、繊維束内などに残留している気泡を十分に脱泡することが好ましい。 The cellulose resin sheet is impregnated with the epoxy resin composition. After impregnation, it is preferable to sufficiently defoam bubbles remaining in the fiber bundle.
　次いで、得られた含浸物を一定の厚み（セルロース系繊維シートの厚みや、最終的に得ようとする複合膜の厚みなどを考慮して適宜設定すればよい）に調整した後に、所定の重合温度に加熱して重合を行う。 Next, after adjusting the obtained impregnated material to a certain thickness (which may be appropriately set in consideration of the thickness of the cellulosic fiber sheet and the thickness of the composite membrane to be finally obtained), a predetermined polymerization is performed. Polymerization is carried out by heating to temperature.
　含浸物を一定の厚みに設定する方法としては、例えば、
（１）ガラスや金属製の平板の上にセルロース系繊維シートとエポキシ樹脂組成物を置き、泡を含まないように含浸させた後に設定の厚さになるようにもう一枚の平板で挟み、硬化する方法、
（２）ガラスや金属製の平板の上にセルロース系繊維シートとエポキシ樹脂組成物を置き、泡を含まないように含浸させた後に設定の厚さになるようにバーコーターのような直線上のもので表面を平らにした後、硬化する方法
（３）ガラスや金属製の平板の上にセルロース系繊維シートと増粘させたエポキシ樹脂組成物を置き、泡を含まないように含浸させた後に、セルロース系繊維シートとエポキシ樹脂組成物を基材から外し、設定の厚さになるように両面からバーコーターやロールコーター、ナイフコーター、ブレードコーターのようなよく知られた（直線状の）塗布装置で表面を平らにした後、硬化する方法、などを挙げることができる。
（４）また、長尺のセルロース系繊維シートを使用する場合は増粘させたエポキシ樹脂組成物を使用してロールコーター、ナイフコーター、ブレードコーターのようなよく知られた塗布装置を使用して連続的に塗布することも出来る。
　上記のうち、（３）の増粘させたエポキシ樹脂組成物を使用する方法は、スキン層（空気と接する表面に孔がないか極めて少ないスキン層）が生じないという利点がある。
　（３）のようにエポキシ樹脂組成物を増粘して使用するのは、（１）、（２）のように平板上の支持基板を用いない状態で、未硬化のエポキシ樹脂組成物が流動性のために垂れたりして膜厚が不均一にならないようにするためであるが、同時にスキン層の形成を防ぐ効果がある。
　増粘剤としては市販のものが種々使用できるが、中でも、微粉シリカが好ましい。微粉シリカとしては「アエロジル」シリーズ（日本アエロジル株式会社製）として販売されているものなどが挙げられ、親水性の表面を持つものが好ましい。また、この増粘剤については、（３）に限らず、（１）、（２）、（４）においても使用することができる。 As a method of setting the impregnated material to a constant thickness, for example,
(1) Place a cellulosic fiber sheet and an epoxy resin composition on a flat plate made of glass or metal, impregnate it so as not to contain bubbles, and sandwich it with another flat plate so as to have a set thickness, How to cure,
(2) Place a cellulosic fiber sheet and an epoxy resin composition on a flat plate made of glass or metal, impregnate so that it does not contain bubbles, and then on a straight line like a bar coater so as to have a set thickness Method of curing after flattening the surface with a material (3) After placing a cellulosic fiber sheet and a thickened epoxy resin composition on a flat plate made of glass or metal, and impregnating so as not to contain bubbles Well-known (linear) coatings such as bar coater, roll coater, knife coater, blade coater from both sides to remove the cellulosic fiber sheet and epoxy resin composition from the substrate and to set thickness A method of curing after flattening the surface with an apparatus can be mentioned.
(4) When using a long cellulose fiber sheet, use a well-known coating device such as a roll coater, knife coater, blade coater using a thickened epoxy resin composition. It can also be applied continuously.
Among the above, the method (3) using the thickened epoxy resin composition has an advantage that a skin layer (a skin layer having no or very few pores on the surface in contact with air) does not occur.
The thickened epoxy resin composition is used as in (3), and the uncured epoxy resin composition flows without using a support substrate on a flat plate as in (1) and (2). This is to prevent the film from sagging due to the property and to make the film thickness non-uniform, but at the same time, it has the effect of preventing the formation of the skin layer.
Various commercially available thickeners can be used as the thickener, and among these, finely divided silica is preferred. Examples of fine silica include those sold as “Aerosil” series (produced by Nippon Aerosil Co., Ltd.), and those having a hydrophilic surface are preferred. Further, the thickener can be used not only in (3) but also in (1), (2), and (4).
　重合誘起により、重合物とポロゲンをスピノーダル分解させることでミクロ相分離を起こさせることができる。そして、ミクロ相分離が生長すると、重合物とポロゲンによる共連続構造が不安定化して粒子凝集構造に転移しようとするが、その前に重合物を三次元架橋させることにより共連続構造体を構造固定（凍結固定）することができる。 Microphase separation can be caused by spinodal decomposition of the polymer and porogen due to polymerization induction. When microphase separation grows, the co-continuous structure due to the polymer and porogen becomes unstable and attempts to transfer to a particle aggregate structure. Before that, the polymer is cross-linked three-dimensionally to form the co-continuous structure. Can be fixed (freeze-fixed).
　このように、含浸物を加熱して硬化物を得る工程は、通常、重合、架橋、相分離、及び硬化の各段階を含み、これらの各段階は、場合により、複合的に進行し得る。 As described above, the process of heating the impregnated product to obtain a cured product usually includes polymerization, crosslinking, phase separation, and curing steps, and these steps may proceed in combination in some cases.
　次いで、得られた硬化物からポロゲンを水あるいはポロゲンを溶解可能で且つエポキシ樹脂が熱分解しない温度以下（適用するエポキシ樹脂によっても異なり得るが、例えば、２００℃以下程度）で熱乾燥可能な溶媒で抽出することによって除去した後、乾燥することにより、三次元網目状骨格構造を有する多孔体を含んでなる複合膜が得られる。 Next, a solvent capable of dissolving the porogen from water or porogen from the obtained cured product and capable of being thermally dried at a temperature not higher than the temperature at which the epoxy resin is not thermally decomposed (which may vary depending on the applied epoxy resin, for example, about 200 ° C. or lower). After removing by extraction with the above, drying is performed to obtain a composite film comprising a porous body having a three-dimensional network skeleton structure.
　ここで、スピノーダル分解を生ぜしめるためには、重合液を臨界組成近傍とすることが重要である。 Here, in order to cause spinodal decomposition, it is important to make the polymerization solution near the critical composition.
　重合が進行し、ポリマー成分が増大すると、スピノーダル分解によって相分離が起こり、共連続構造が発現するが、上記のとおり、相分離が更に進行し、共連続構造が消滅する前にエポキシ樹脂の架橋反応を進行させることにより構造が固定されて、所望の三次元網目状骨格構造、又は三次元網目状骨格と球状微粒子が混在する三次元網目状骨格構造、及び連通する空隙を有する多孔体を製造することが可能となる。
　得られた多孔体の構造は、例えば、走査型電子顕微鏡観察によって確認することができる。 As polymerization progresses and the polymer component increases, phase separation occurs due to spinodal decomposition and a co-continuous structure develops, but as described above, the phase separation further proceeds and the epoxy resin crosslinks before the co-continuous structure disappears. The structure is fixed by advancing the reaction to produce a desired three-dimensional network skeleton structure, or a three-dimensional network skeleton structure in which three-dimensional network skeleton and spherical fine particles are mixed, and a porous body having communicating voids. It becomes possible to do.
The structure of the obtained porous body can be confirmed by, for example, observation with a scanning electron microscope.
　本発明の複合膜における上記の空孔率、平均孔径及び孔径分布は、用いるエポキシ樹脂、硬化剤及びポロゲンの種類や使用比率、あるいは重合温度条件により変化する。従って、系の相図を作成し、最適な条件を選択することにより、上記範囲の空孔率、平均孔径及び孔径分布を得ることができる。 The above-mentioned porosity, average pore diameter, and pore diameter distribution in the composite membrane of the present invention vary depending on the type and usage ratio of the epoxy resin, curing agent and porogen used, or polymerization temperature conditions. Therefore, by creating a phase diagram of the system and selecting optimum conditions, the porosity, average pore diameter, and pore diameter distribution in the above range can be obtained.
　〔複合膜の用途〕
　本発明の複合膜は、薄膜で十分な機械強度を有すると共に、十分なイオン通過性や通気性ないし通水性を有するので、リチウムイオン電池などの二次電池用のセパレータや濾過剤などとして利用することができる。
　また、セルロース系繊維シートとの複合化で強度が向上していることから得られた複合膜を円筒状や箱形などの平面的利用以外の形状に加工して使用することも出来る。 [Use of composite membrane]
The composite membrane of the present invention is a thin film and has sufficient mechanical strength, and has sufficient ion permeability, air permeability, and water permeability. Therefore, the composite membrane is used as a separator for a secondary battery such as a lithium ion battery or a filtering agent. be able to.
Moreover, the composite film obtained from the fact that the strength is improved by compounding with the cellulosic fiber sheet can be used after being processed into a shape other than planar use such as a cylindrical shape or a box shape.
　以下に、実施例を挙げて、本発明についてより具体的に説明するが、本発明は、これら実施例に限定されない。
　以下では、まず、実施例等における物性等の評価方法について示したのち、次いで、各実施例、比較例の内容及びそれらの評価・考察を示す。 Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Below, after showing about the evaluation method of the physical property etc. in an Example etc. first, next, the content of each Example and a comparative example, and those evaluation and consideration are shown.
〔実施例等における物性等の評価方法〕
　＜多孔体の構造＞
　走査型電子顕微鏡によって多孔体の断面写真を撮影し、多孔体の構造を観察した。 [Evaluation method for physical properties in Examples, etc.]
<Structure of porous body>
A cross-sectional photograph of the porous body was taken with a scanning electron microscope, and the structure of the porous body was observed.
　＜空孔率＞
　複合膜の空孔率は、次の式によって算出した。
　空孔率（％）＝（１－Ｗ／ρＶ）×１００
　ここで、
　Ｗ：複合膜の乾燥重量（ｇ）
　Ｖ：複合膜の見掛けの体積（ｃｍ3）
　ρ：複合膜の固形分密度（ｇ／ｍ3）
である。尚、ここで複合膜の固形分密度は、複合膜をエタノールに入れて脱泡後、ＪＩＳ－Ｋ－７１１２（Ｂ法Ｉ）に従い測定した値である。 <Porosity>
The porosity of the composite membrane was calculated by the following formula.
Porosity (%) = (1−W / ρV) × 100
here,
W: Dry weight of composite membrane (g)
V: Apparent volume of the composite membrane (cm 3 )
ρ: solid content density of composite membrane (g / m 3 )
It is. Here, the solid content density of the composite membrane is a value measured according to JIS-K-7112 (Method B) after defoaming the composite membrane in ethanol.
　＜平均的孔径＞
　電子顕微鏡写真から概算した。複合膜の平均孔径は、通常、この複合膜の平均的孔径の数値範囲内にあると理解できる。 <Average pore size>
Estimated from electron micrographs. It can be understood that the average pore size of the composite membrane is usually within the numerical range of the average pore size of the composite membrane.
　＜引張強さ＞
　幅１ｃｍ長さ５ｃｍのサンプルを作成し、引張り試験器「テンシロン」（株式会社エー・アンド・デイ社製）で測定した。 <Tensile strength>
A sample having a width of 1 cm and a length of 5 cm was prepared and measured with a tensile tester “Tensilon” (manufactured by A & D Corporation).
〔実施例等で使用した繊維シートの詳細〕
　後述の実施例及び比較例では、下表に示すセルロース系繊維シート及びＰＥＴ紙を用いた。
　セルロース系繊維シート１は日本製紙パピリア株式会社製の「超極薄紙」でありセルロース系繊維シート２、３及びＰＥＴ紙も同社製（の試作品）である。 [Details of the fiber sheet used in Examples etc.]
In Examples and Comparative Examples described later, the cellulosic fiber sheets and PET paper shown in the following table were used.
Cellulose-based fiber sheet 1 is “ultra-thin paper” manufactured by Nippon Paper Papillia Co., Ltd., and cellulose-based fiber sheets 2 and 3 and PET paper are also manufactured by (the prototype).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
〔実施例１〕
＜エポキシ樹脂組成物の調製＞
　エポキシ樹脂として、エポキシ当量が９５～１１０（平均１０２）である下記式（１）で表されるエポキシ化合物（商品名「テトラッドーＣ」、三菱ガス化学工業株式会社）１重量部、硬化剤として、アミン価が５２０～５５０である下記式（２）で表されるビス（４－アミノシクロヘキシル）メタン（東京化成工業株式会社製）０．５７５重量部、ポロゲンとして、平均分子量が２００である下記式（３）で表されるポリエチレングリコール２００（和光純薬工業株式会社製）４重量部を用い、これらを、自転・公転ミキサーの「あわとり練太郎」で混合することで、エポキシ樹脂組成物を得た。粘度は２５℃で１３５ｍＰａ・Ｓであった（粘度計は振動式粘度計「ＶＭ－１０－ＡＭ、株式会社セコニック製」を使用）。 [Example 1]
<Preparation of epoxy resin composition>
As an epoxy resin, 1 part by weight of an epoxy compound represented by the following formula (1) having an epoxy equivalent of 95 to 110 (average 102) (trade name “Tetrad-C”, Mitsubishi Gas Chemical Industries, Ltd.), as a curing agent, 0.575 parts by weight of bis (4-aminocyclohexyl) methane (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (2) having an amine value of 520 to 550, the following formula having an average molecular weight of 200 as a porogen Using 4 parts by weight of polyethylene glycol 200 represented by (3) (manufactured by Wako Pure Chemical Industries, Ltd.) and mixing them with “Awatori Netaro” of a rotation / revolution mixer, an epoxy resin composition is obtained. Obtained. The viscosity was 135 mPa · S at 25 ° C. (The viscometer used was a vibration viscometer “VM-10-AM, manufactured by Seconic Corporation”).
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　＜複合膜の作製＞
　平均重合度ｎが３５００、鹸化度が８６～９０％であるポリビニルアルコール（ＰＶＡ）（和光純薬工業株式会社製）の２重量％水溶液を、７５ｍｍ×７５ｍｍのガラス板２枚に、スピンコーターを用いて２，０００ｒｐｍ、２０秒の条件で塗布した後、１０５℃で１時間のアニール処理を施すことによって、ポリビニルアルコール層を形成したガラス板を２枚得た。 <Production of composite membrane>
A 2 wt% aqueous solution of polyvinyl alcohol (PVA) (manufactured by Wako Pure Chemical Industries, Ltd.) having an average polymerization degree n of 3500 and a saponification degree of 86 to 90% was applied to two 75 mm × 75 mm glass plates with a spin coater. Then, after coating at 2,000 rpm for 20 seconds, annealing was performed at 105 ° C. for 1 hour to obtain two glass plates on which a polyvinyl alcohol layer was formed.
　次いで、ポリビニルアルコール層を形成したガラス板のポリビニルアルコール層形成面に、ガラス板と同じ大きさに切断した表１記載のセルロース系繊維シート１（日本製紙パピリア株式会社の「超極薄紙」（坪量６ｇ／ｍ2、厚さ１６μｍ、麻と木材繊維使用、セルロース繊維の比重を１．５として計算すると空隙率は７４％））を置いた。
　上記にて調製したエポキシ樹脂組成物を繊維シートの中央部に置き、この上に、ポリビニルアルコール層を形成した別のガラス板を、ポリビニルアルコール層形成面が、エポキシ樹脂組成物層と接触するように、直接、エポキシ樹脂組成物層上に載せた。このとき、気泡が混入しないよう、エポキシ樹脂組成物が静かに繊維シート全体を覆うように留意した。
　そして、余分なエポキシ樹脂組成物が２枚のガラス板の間から出てくるようにして軽く手で圧着してあふれた液を除き、その後、ダブルクリップ等で２枚のガラス板を四方向から軽く固定した。 Next, on the polyvinyl alcohol layer-forming surface of the glass plate on which the polyvinyl alcohol layer was formed, the cellulose fiber sheet 1 shown in Table 1 cut to the same size as the glass plate (“Ultra-thin paper” from Nippon Paper Papillia Co., Ltd.) The amount was 6 g / m 2 , the thickness was 16 μm, hemp and wood fiber used, and the specific gravity of cellulose fiber was calculated as 1.5, and the porosity was 74%)).
The epoxy resin composition prepared above is placed in the center of the fiber sheet, and another glass plate on which the polyvinyl alcohol layer is formed is placed on the epoxy resin composition so that the polyvinyl alcohol layer-forming surface is in contact with the epoxy resin composition layer. And placed directly on the epoxy resin composition layer. At this time, attention was paid so that the epoxy resin composition gently covered the entire fiber sheet so that bubbles would not be mixed.
Then, the excess epoxy resin composition comes out between the two glass plates, lightly crimped by hand to remove the overflowed liquid, and then lightly fix the two glass plates from four directions with a double clip etc. did.
　上記のようにしてエポキシ樹脂組成物を繊維シートに含浸して得られた含浸物を挟んだガラス板を、１１０℃で１時間加熱することにより、エポキシ樹脂組成物層中のエポキシ化合物を硬化させ、硬化物を得た。次いで、硬化物を温度８０～９０℃に調整した温水中に投入し、６０分間放置することによりポリビニルアルコール層の一部を溶解させることで、ガラス板から剥離させた。ついで、硬化物を温度５０～６０℃に調整した純水からなる温水中に投入し、温水を適宜撹拌しつつ２時間放置することにより、加熱後のエポキシ樹脂組成物層中に含有するポリエチレングリコール２００を抽出する工程を３回繰り返した後、６０℃の真空下で１晩乾燥させて、繊維シートとエポキシ樹脂硬化物多孔体からなるスキン層のない複合膜を得た。 The glass plate sandwiched with the impregnated material obtained by impregnating the fiber sheet with the epoxy resin composition as described above is heated at 110 ° C. for 1 hour to cure the epoxy compound in the epoxy resin composition layer. A cured product was obtained. Next, the cured product was poured into warm water adjusted to a temperature of 80 to 90 ° C. and left for 60 minutes to dissolve a part of the polyvinyl alcohol layer, thereby peeling off the glass plate. Next, the cured product is poured into warm water composed of pure water adjusted to a temperature of 50 to 60 ° C., and left for 2 hours with proper stirring of the warm water, whereby polyethylene glycol contained in the epoxy resin composition layer after heating is contained. The process of extracting 200 was repeated three times and then dried overnight at 60 ° C. under vacuum to obtain a composite film without a skin layer composed of a fiber sheet and a porous epoxy resin cured product.
　得られた複合膜の厚みは２４μｍ、繊維含有率は３５重量％、複合膜の空孔率は４３％であり、走査型電子顕微鏡で確認した複合膜の平均的孔径は０．８～１．２μｍであった。複合膜引張強さはＭＤ方向（繊維シートの繊維方向）が７５．４ＭＰａ、ＣＤ方向（繊維シートの繊維と直角方向）が１７．３ＭＰａであった。また、得られた複合膜について、複素インピーダンス測定によりイオン導電性を測定したところ、１０-4Ｓ／ｃｍ以上となり高いイオン導電性を有していることが確認できた。
　また、得られた複合膜について、走査型電子顕微鏡（ＳＥＭ）写真を図１及び図２に示す。図１は、上記複合膜を切断して撮影したモノリス構造断面のＳＥＭ写真であり、図２は、上記複合膜における膜表面のＳＥＭ写真である。 The thickness of the obtained composite membrane was 24 μm, the fiber content was 35% by weight, the porosity of the composite membrane was 43%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.8 to 1. It was 2 μm. The composite film tensile strength was 75.4 MPa in the MD direction (fiber direction of the fiber sheet) and 17.3 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet). Further, when the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 −4 S / cm or more, and it was confirmed that the ionic conductivity was high.
Moreover, about the obtained composite film, a scanning electron microscope (SEM) photograph is shown in FIG.1 and FIG.2. FIG. 1 is an SEM photograph of a cross section of the monolith structure taken by cutting the composite film, and FIG. 2 is an SEM photograph of the film surface of the composite film.
〔実施例２〕
　実施例１において、上記表１記載のセルロース系繊維シート１に代えて、上記表１記載のセルロース系繊維シート２を用いたこと以外は実施例１と同様にして、実施例２に係る複合膜を得た。
　得られた複合膜の厚みは３８．２μｍ、複合膜の空孔率は４９％であり、走査型電子顕微鏡で確認した複合膜の平均的孔径は０．８～１．２μｍであった。複合膜引張強さはＭＤ方向（繊維シートの繊維方向）が４０．６ＭＰａ、ＣＤ方向（繊維シートの繊維と直角方向）が２３．１ＭＰａであった。また、得られた複合膜について、複素インピーダンス測定によりイオン導電性を測定したところ、１０-4Ｓ／ｃｍ以上となり高いイオン導電性を有していることが確認できた。 [Example 2]
In Example 1, it replaced with the cellulose fiber sheet 1 of the said Table 1, and it replaced with the cellulose fiber sheet 2 of the said Table 1, and was the same as Example 1, and the composite film which concerns on Example 2 Got.
The thickness of the obtained composite membrane was 38.2 μm, the porosity of the composite membrane was 49%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.8 to 1.2 μm. The composite film tensile strength was 40.6 MPa in the MD direction (fiber direction of the fiber sheet) and 23.1 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet). Further, when the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 −4 S / cm or more, and it was confirmed that the ionic conductivity was high.
〔実施例３〕
　実施例１において、上記表１記載のセルロース系繊維シート１に代えて、上記表１記載のセルロース系繊維シート３を用いたこと以外は実施例１と同様にして、実施例３に係る複合膜を得た。
　得られた複合膜の厚みは５３．７μｍ、複合膜の空孔率は５０％であり、走査型電子顕微鏡で確認した複合膜の平均的孔径は０．８～１．２μｍであった。複合膜引張強さはＭＤ方向（繊維シートの繊維方向）が３３．７ＭＰａ、ＣＤ方向（繊維シートの繊維と直角方向）が２２．３ＭＰａであった。また、得られた複合膜について、複素インピーダンス測定によりイオン導電性を測定したところ、１０-4Ｓ／ｃｍ以上となり高いイオン導電性を有していることが確認できた。 Example 3
In Example 1, it replaced with the cellulose fiber sheet 1 of the said Table 1, and it replaced with the cellulose fiber sheet 3 of the said Table 1, and it was the same as that of Example 1, and the composite film which concerns on Example 3 Got.
The thickness of the obtained composite membrane was 53.7 μm, the porosity of the composite membrane was 50%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.8 to 1.2 μm. The composite film tensile strength was 33.7 MPa in the MD direction (fiber direction of the fiber sheet) and 22.3 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet). Further, when the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 −4 S / cm or more, and it was confirmed that the ionic conductivity was high.
〔実施例４〕
　実施例１のエポキシ樹脂組成物に増粘剤として、アエロジル１３０（日本アエロジル株式会社製）をポリエチレングリコール２００に対して５重量％となる割合で用いて、自転・公転ミキサーの「あわとり練太郎」で混合することで、増粘したエポキシ樹脂組成物を得た。粘度は２５℃で８４０ｍＰａ・Ｓであった（粘度計は振動式粘度計「ＶＭ－１０－ＡＭ、株式会社セコニック製」を使用）。
　次に、市販の４０ｃｍ角ガラス板の上に、１５ｃｍ×３０ｃｍの大きさに切断した表１記載のセルロース系繊維シート１（日本製紙パピリア株式会社の「超極薄紙」（坪量６ｇ／ｍ2、厚さ１６μｍ、麻と木材繊維使用、セルロース繊維の比重を１．５として計算すると空隙率は７４％））を置き、増粘したエポキシ樹脂組成物を繊維シートの中央部に置き、ガラス棒で繊維シート全体に行き渡るように伸ばして含浸させた後に、軽く押さえたバーコーター（Ｎｏ．３）２本の間を通して引き上げることにより均一な膜厚の含浸物を得た。これを１１０℃の高温乾燥機中で１時間加熱して硬化させ、硬化物を得た。ついで、硬化物を温度５０～６０℃に調整した温水中に投入し、温水を適宜撹拌しつつ２時間放置することにより、加熱後のエポキシ樹脂組成物層中に含有するポリエチレングリコール２００を抽出する工程を３回繰り返した。その後、６０℃の真空下で一晩乾燥させた。 Example 4
As the thickener for the epoxy resin composition of Example 1, Aerosil 130 (manufactured by Nippon Aerosil Co., Ltd.) was used in a proportion of 5% by weight with respect to polyethylene glycol 200. ”To obtain a thickened epoxy resin composition. The viscosity was 840 mPa · s at 25 ° C. (The viscometer used was a vibration viscometer “VM-10-AM, manufactured by Seconic Corporation”).
Next, on a commercially available 40 cm square glass plate, the cellulosic fiber sheet 1 shown in Table 1 cut into a size of 15 cm × 30 cm (“ultra-thin paper” from Nippon Paper Papillia Co., Ltd.) (basis weight 6 g / m 2 The thickness is 16 μm, hemp and wood fibers are used, and the specific gravity of cellulose fiber is calculated as 1.5. The porosity is 74%)), and the thickened epoxy resin composition is placed in the center of the fiber sheet. After extending and impregnating so as to spread over the entire fiber sheet, an impregnation product having a uniform film thickness was obtained by pulling it up through two lightly pressed bar coaters (No. 3). This was cured by heating for 1 hour in a high-temperature dryer at 110 ° C. to obtain a cured product. Subsequently, the cured product is poured into warm water adjusted to a temperature of 50 to 60 ° C., and left for 2 hours while appropriately stirring the warm water, thereby extracting the polyethylene glycol 200 contained in the heated epoxy resin composition layer. The process was repeated 3 times. Then, it was dried overnight at 60 ° C. under vacuum.
　得られた複合膜の厚みは２３μｍ、繊維含有率は３５重量％、複合膜の空孔率は４３％であり、走査型電子顕微鏡で確認した複合膜の平均的孔径は０．２～０．５μｍであった。複合膜引張強さはＭＤ方向（繊維シートの繊維方向）が７０．５ＭＰａ、ＣＤ方向（繊維シートの繊維と直角方向）が１６．３ＭＰａであった。また、得られた複合膜について、複素インピーダンス測定によりイオン導電性を測定したところ、１０-4Ｓ／ｃｍ以上となり高いイオン導電性を有していることが確認できた。
　また、得られた複合膜について、走査型電子顕微鏡（ＳＥＭ）写真を図３に示す。図３は、上記複合膜における膜表面のＳＥＭ写真であり、スキン層のない表面をもっている（表面に孔がある）ことが分かる。 The thickness of the obtained composite membrane was 23 μm, the fiber content was 35% by weight, the porosity of the composite membrane was 43%, and the average pore size of the composite membrane confirmed by a scanning electron microscope was 0.2 to 0.00. It was 5 μm. The composite film tensile strength was 70.5 MPa in the MD direction (fiber direction of the fiber sheet) and 16.3 MPa in the CD direction (direction perpendicular to the fibers of the fiber sheet). Further, when the ionic conductivity of the obtained composite membrane was measured by complex impedance measurement, it was 10 −4 S / cm or more, and it was confirmed that the ionic conductivity was high.
Moreover, a scanning electron microscope (SEM) photograph of the obtained composite film is shown in FIG. FIG. 3 is an SEM photograph of the film surface in the composite film, and it can be seen that it has a surface without a skin layer (has holes on the surface).
〔比較例１〕
　実施例１と同様の方法で、セルロース系繊維シート１の代わりに厚さ２５μｍのテフロン（登録商標）フィルムを３ｍｍの幅に切ってガラス板の４辺の周辺部に置いてスペーサーとし、エポキシ樹脂組成物だけで膜を形成した。
　得られたエポキシ多孔体の厚みは２３μｍで、引張強さは１０．４ＭＰａで（繊維シートを入れていないので強度に方向性はない）、走査型電子顕微鏡で確認したエポキシ多孔体の平均的孔径は０．８～１．２μｍであった。また、得られた多孔膜について、複素インピーダンス測定によりイオン導電性を測定したところ、１０-4Ｓ／ｃｍ以上となり高いイオン導電性を有していることが確認できた。 [Comparative Example 1]
In the same manner as in Example 1, instead of the cellulosic fiber sheet 1, a 25 μm-thick Teflon (registered trademark) film was cut to a width of 3 mm and placed on the periphery of the four sides of the glass plate to form a spacer. A film was formed only with the composition.
The resulting epoxy porous body had a thickness of 23 μm and a tensile strength of 10.4 MPa (the fiber sheet was not inserted so that there was no directionality in the strength), and the average pore diameter of the epoxy porous body confirmed with a scanning electron microscope Was 0.8 to 1.2 μm. Further, when the ionic conductivity of the obtained porous membrane was measured by complex impedance measurement, it was 10 −4 S / cm or more, and it was confirmed that the ionic conductivity was high.
〔比較例２〕
　実施例１において、上記表１記載のセルロース系繊維シート１に代えて、上記表１記載のＰＥＴ紙を用いたこと以外は実施例１と同様にして、比較例２に係る複合膜を得た。
　得られた複合膜の厚みは１３μｍで、複合膜の空孔率は２３％であり、引張強さはＭＤ方向（繊維シートの繊維方向）が２４．８ＭＰａで、ＣＤ方向（繊維シートの繊維と直角方向）が９．８ＭＰａで、複合前のＰＥＴ紙と殆ど変わりがなかった。走査型電子顕微鏡で確認した複合膜の平均的孔径は０．８～１．２μｍであった。 [Comparative Example 2]
In Example 1, it replaced with the cellulose fiber sheet 1 of the said Table 1, and obtained the composite film which concerns on the comparative example 2 like Example 1 except having used the PET paper of the said Table 1. .
The thickness of the obtained composite membrane was 13 μm, the porosity of the composite membrane was 23%, the tensile strength was 24.8 MPa in the MD direction (fiber direction of the fiber sheet), and the CD direction (with the fibers of the fiber sheet) (Perpendicular direction) was 9.8 MPa, which was almost the same as that of the PET paper before composite. The average pore size of the composite membrane confirmed with a scanning electron microscope was 0.8 to 1.2 μm.
〔物性のまとめ〕
　各実施例及び比較例について、物性を下表２にまとめた。なお、表２において、イオン導電率については、１０-4Ｓ／ｃｍ以上を「○」と表記している。また、「－」の表記は、測定ができないか無意味であるため測定していないことを意味する。 [Summary of physical properties]
The physical properties of each Example and Comparative Example are summarized in Table 2 below. In Table 2, for ion conductivity, 10 −4 S / cm or more is expressed as “◯”. The notation “-” means that measurement is not possible because it is impossible or meaningless.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
〔結果についての考察〕　実施例１～４に示す結果から、セルロース系繊維シートとエポキシ樹脂硬化物多孔体との複合膜は、薄膜でありながら、多孔性を大きく低下させることなく、それぞれの材料の強度の足し算以上の強度を持つ材料が得られることが分かった。
　一方、各実施例と比較例２との比較から、単に繊維シートを用いればよいというのではなく、セルロース系繊維シートを用いることが重要であることが分かった。
　実施例１と実施例４を比較すると、実施例４の方が孔径が小さいことが分かる。これは、実施例４では、実施例１と異なり、硬化時にガラス板がないため、直接加熱となり実質硬化温度が高いことから孔径が小さくなったと推定される。 [Consideration of Results] From the results shown in Examples 1 to 4, the composite film of the cellulose fiber sheet and the cured epoxy resin porous material is a thin film, and the respective materials without greatly reducing the porosity. It was found that a material having a strength equal to or greater than the addition of the above strengths can be obtained.
On the other hand, it was found from the comparison between each example and Comparative Example 2 that it is important to use a cellulosic fiber sheet rather than simply using a fiber sheet.
Comparing Example 1 and Example 4, it can be seen that Example 4 has a smaller hole diameter. In Example 4, unlike Example 1, since there is no glass plate at the time of curing, it is presumed that the hole diameter was reduced because it was directly heated and the substantial curing temperature was high.

Claims (10)

  1. 　三次元網目状骨格構造及び連通する空隙を有するエポキシ樹脂硬化物多孔体とセルロース系繊維シートとを含んでなる、複合膜。 A composite film comprising a porous epoxy resin cured material having a three-dimensional network skeleton structure and communicating voids and a cellulose fiber sheet.
  2. 　空孔率が２０％～７０％、平均孔径が０．１～１０μｍである、請求項１に記載の複合膜。 2. The composite membrane according to claim 1, having a porosity of 20% to 70% and an average pore diameter of 0.1 to 10 μm.
  3. 　厚みが１０～１００μｍである、請求項１又は２に記載の複合膜。 3. The composite membrane according to claim 1, wherein the thickness is 10 to 100 μm.
  4. 　二次電池のセパレータとして利用される、請求項１から３までのいずれかに記載の複合膜。 The composite membrane according to any one of claims 1 to 3, which is used as a separator for a secondary battery.
  5. 　エポキシ樹脂、硬化剤及びポロゲンを含むエポキシ樹脂組成物をセルロース系繊維シートに含浸し、得られた含浸物を加熱して前記エポキシ樹脂を硬化し、得られた硬化物から前記ポロゲンを除去する、複合膜の製造方法。 Impregnating a cellulosic fiber sheet with an epoxy resin composition containing an epoxy resin, a curing agent and a porogen, heating the resulting impregnated product to cure the epoxy resin, and removing the porogen from the resulting cured product; A method for producing a composite membrane.
  6. 　前記含浸の際に用いる前記エポキシ樹脂組成物が増粘剤をも含むものである、請求項５に記載の複合膜の製造方法。 The method for producing a composite film according to claim 5, wherein the epoxy resin composition used in the impregnation also contains a thickener.
  7. 　前記増粘剤が微粉シリカである、請求項６に記載の複合膜の製造方法。 The method for producing a composite film according to claim 6, wherein the thickener is finely divided silica.
  8. 　前記含浸物を加熱して硬化する前に、２本のバーコーターの間を通して厚み調整する、請求項６又は７に記載の複合膜の製造方法。 The method for producing a composite film according to claim 6 or 7, wherein the thickness is adjusted between two bar coaters before the impregnated material is heated and cured.
  9. 　前記含浸の際に用いる前記セルロース系繊維シートの空隙率が５０％以上である、請求項５から８までのいずれかに記載の複合膜の製造方法。 The method for producing a composite membrane according to any one of claims 5 to 8, wherein the cellulosic fiber sheet used in the impregnation has a porosity of 50% or more.
  10. 　前記含浸の際に用いる前記セルロース系繊維シートの厚みが１～１０００μｍである、請求項５から９までのいずれかに記載の複合膜の製造方法。 10. The method for producing a composite membrane according to claim 5, wherein the cellulosic fiber sheet used for the impregnation has a thickness of 1 to 1000 μm.
PCT/JP2016/073299 2015-08-10 2016-08-08 Composite film and method for producing same WO2017026445A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2015-157891 2015-08-10
JP2015157891A JP6522464B2 (en) 2015-08-10 2015-08-10 Composite membrane and method for producing the same

Publications (1)

Publication Number Publication Date
WO2017026445A1 true WO2017026445A1 (en) 2017-02-16

Family

ID=57984539

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/073299 WO2017026445A1 (en) 2015-08-10 2016-08-08 Composite film and method for producing same

Country Status (2)

Country Link
JP (1) JP6522464B2 (en)
WO (1) WO2017026445A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7486741B2 (en) 2020-06-08 2024-05-20 東芝キヤリア株式会社 Compressor and refrigeration cycle device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102293299B1 (en) * 2018-10-15 2021-08-23 세종대학교산학협력단 Nano-cellulose composite, method for producing the same, and separator for secondary battery manufactured therefrom
WO2020179642A1 (en) 2019-03-04 2020-09-10 株式会社エマオス京都 Porous body, and method for producing porous body

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008013672A (en) * 2006-07-06 2008-01-24 Kyoto Institute Of Technology Composite material containing cured epoxy resin porous material and fiber
WO2014207308A1 (en) * 2013-06-28 2014-12-31 Upm-Kymmene Corporation A fiber mat reinforced resin composite

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008013672A (en) * 2006-07-06 2008-01-24 Kyoto Institute Of Technology Composite material containing cured epoxy resin porous material and fiber
WO2014207308A1 (en) * 2013-06-28 2014-12-31 Upm-Kymmene Corporation A fiber mat reinforced resin composite

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7486741B2 (en) 2020-06-08 2024-05-20 東芝キヤリア株式会社 Compressor and refrigeration cycle device

Also Published As

Publication number Publication date
JP6522464B2 (en) 2019-05-29
JP2017036381A (en) 2017-02-16

Similar Documents

Publication Publication Date Title
US20220072485A1 (en) Anion exchange polymers and anion exchange membranes incorporating same
US7740967B2 (en) Highly conductive ordered ion exchange membranes
JP2008013672A (en) Composite material containing cured epoxy resin porous material and fiber
WO2017026445A1 (en) Composite film and method for producing same
US11987680B2 (en) Composite ion exchange membrane and method of making same
Cheng et al. Enhanced pervaporation performance of polyamide membrane with synergistic effect of porous nanofibrous support and trace graphene oxide lamellae
CN112135867B (en) Pore-filled ion-exchange polymer electrolyte composite membrane from which surface ion-exchange polymer electrolyte has been removed, and method for producing same
KR20160026070A (en) Manufacturing method of gas separator membrane
CN111116963B (en) Preparation method of ceramic coating diaphragm, diaphragm and ceramic coating slurry
CN110743381B (en) Membrane substrate, separation membrane and preparation method thereof
KR101875812B1 (en) An ion-exchange membrane and porous substrate for water treatment and manufacturing method of it
JP6579791B2 (en) Method for producing polyethersulfone fiber assembly
CN113117539A (en) Reverse osmosis membrane based on modified polyolefin substrate and preparation method thereof
JP7409777B2 (en) Separator for lithium ion secondary batteries
JP2010155204A (en) Method of producing composite hollow fiber membrane
JP2016089197A (en) Base material for alkali water electrolysis diaphragm
JP5865761B2 (en) Porous membrane manufacturing method, electrolyte membrane manufacturing method, secondary battery manufacturing method, and fuel cell manufacturing method
WO2014142381A1 (en) Method for manufacturing pollution-proof nanofiber separation film and pollution-proof nanofiber separation film manufactured thereby
CN113893710B (en) High-flux polyethylene water treatment membrane and preparation method thereof
WO2017052185A1 (en) Method for producing polymer filtration membrane and polymer filtration membrane
JP4969192B2 (en) Porous film and method for producing the same
KR20200129692A (en) Separator for secondary battery comprising dispersing agent and manufacturing method thereof
CN109742294B (en) Preparation method of cellulose diaphragm
CN114870644B (en) Semipermeable membrane composite material and preparation method thereof
CN112652813B (en) Biological gel electrolyte composed of PAN and modified PLLA and preparation method thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16835142

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16835142

Country of ref document: EP

Kind code of ref document: A1